Method for producing an enamelware article having a patterned surface



United States Patent 3,453,133 METHOD FOR PRODUCING AN ENAMELWAREARTICLE HAVING A PATTERNED SURFACE William C. Cawthon, New Canaan,Conn., and Robert J. Ulrich, Lyndon, Ky., assignors to American StandardInc., a corporation of Delaware No Drawing. Filed Mar. 7, 1966, Ser. No.532,090 Int. Cl. B44c 1/22; B44d N US. Cl. 11710 6 Claims ABSTRACT OFTHE DISCLOSURE Method for producing an enamelware article having apatterned surface which involves applying to an object to be enameled acoating of dry enamel powder, placing in contact with the coating aglass fiber cloth, and firing the dry enamel powder and the glass fibercloth in contact therewith.

This invention relates to enamelware. More specifically, this inventionrelates to methods for applying useful and decorative surface finishesto enameled articles or portions thereof.

In many applications of enameled articles, the glossy surface normallycharacteristic of such articles is objectionable for one reason'oranother. In architectrual applications, it may be desired to provide amatte finish for esthetic reasons or, particularly in exteriorenvironments, to prevent objectionable glare from the glossy surface. Inother cases, particularly in the production of bathtubs, shower floorsand the like, the smoothness of the normal glossy surface isobjectionable because of the hazard of slippage. Various methods haveheretofore been proposed for developing matte or roughened surfaces onenameled articles, but in most cases they were less than whollysuccessful for a variety of reasons. In general such methods resulted inthe production of a surface characterized by minute surfaceirregularities. If, however, these irregularities were sufficientlylarge in size to afford any effective degree of non-skid action, theyproduced an undesirable sandy or unfinished appearance, and tended totrap and hold dirt, so that cleaning was difiicult.

Various methods have also been proposed for application of decorativecolored designs to enameled surfaces. These have included a number ofmethods which involved the initial preparation of a liquid suspension ofcolored oxides, which could subsequently be applied either to fired orto unfired enamelware, and subsequently fired on. Other processesinvolved the application of the colorants in dry powder form to a firedor unfired piece, with an undercoating of fixative or the like, ifneeded, to hold the powdered colors in place until firing. All of thesemethods, essentially, required that the design be formed directly on theenamelware article, either by painting, stenciling, or the like. Inapplications requiring the use of several colors, it is generallynecessary to apply the liquid or solid colorants to the workpiece one ata time, one over the other, frequently with extra drying or firing stepsin between applications of the various colors. A mistake in positioningof any one of the colored elements of the design could destroy thedesign to the extent that it could not be economically salvaged.

Moreover, in virtually all of the methods heretofore proposed, additionsof any kind, whether in the nature of colorants or skid-resistingmaterials, were necessarily made while the workpiece was at or nearnormal room temperature. This is undesirable because of the resultingincreased demand on fuel and furnace capacity involved in cooling afired piece to room temperature and then, after application of theadditive, reheating it to firing 3,453,133 Patented July 1, 1969temperature. It is additionally undesirable because the additionalheating and subsequent cooling of the piece increases the possibilitiesfor development of strains which may lead to cracking or spalling of thefinish, resulting in rejects.

An object of this invention, therefore, is to provide improved methodsfor producing non-skid surfaces on enameled articles.

Another object is to provide methods for producing such non-skidsurfaces, which do not at the same time produce an undesirable sandy orunfinished appearance.

Still another object is to provide such methods, which provide readilycleanable non-skid surfaces.

A further object is to provide improved methods for the application ofdesigns and indicia of various kinds to enamelware surfaces.

Another object is to provide methods for application of multicolordesigns and indicia to enamelware surfaces, which avoid the necessity ofbuilding up a design by successive applications of different colorants.

Yet another object is to provide methods whereby designs may be createdon a carrier separate from the enameled article, and subsequentlytransferred to said enameled article.

Another object of the invention is to provide a method whereby thetransfer of colorants and/or antiskid materials to the workpiece may bemade while the workpiece is at an elevated temperature.

A feature of the invention is the use of glass fiber cloth as a mediumfor imprinting a non-skid pattern in the surface of an enameled article.

Another feature is the application of glass fiber cloth to an enemeledarticle bearing one or more fired coats of enamel and an unfired coat ofenamel material, and firing the unfired coat in contact with the glassfiber cloth.

Still another feature resides in the application of a ceramic colorantto an enamel by applying to said enamel while still in the unfiredcondition, a glass fiber cloth bearing said colorant and firing saidenamel while in contact with the glass fiber cloth and the colorantthereon.

Other objects, features and advantages will become apparent from thefollowing more complete description and claims.

In one particularly desirable embodiment, this invention contemplates anarticle of enamelware having a surface, at least part of said surfacehaving a patterned texture corresponding to the texture of a clothfabric.

In another particularly desirable embodiment, this inventioncontemplates a method for producing an enamelware article having apatterned surface, comprising the steps of applying to an object to beenameled a coating of dry enamel powder, placing in contact with saidcoating a glass fiber cloth, and firing said dry enamel and said glassfiber cloth in contact therewith.

In still another embodiment, this invention contemplates a method forproducing an enameled article having thereon a design of a colordifferent from the color of the enamel, comprising the steps of applyingto an object to be enameled a coating of dry enamel powder, placing incontact with 'said coating a glass fiber cloth having a ceramic colorantthereon, and firing said enamel coating and said glass fiber cloth andcolorant in contact therewith.

The articles and methods of this invention are particularly useful inconnection with bathtubs, shower floors and the like, where thepatterned or textured surface is advantageous for its non-skidproperties. It is also useful in many other applications, simply for thepleasing appearance created by the duplication in the fired enamelsurface, of the texture and pattern of the glass fiber cloth. In eithertype of application, the appearance of the article may be enhanced byusing the glass fiber cloth as a 3 medium for applying colorants to thearticle, either in the form of a single overall color coextensive withthe textured portion of the surface, or as a design in one or morecolors, which may be placed initially ori'the glass fiber cloth andtransferred from the cloth to the enamelware'article during firing.

The methods of this invention are applicable to enamelware articlesgenerally, and an article which is to receive only a single coat ofenamel may be treated so that'the single enamel coat is textured byfiring it in contact with glass fiber cloth. In accordance withconventional practice, however, it is more usual to apply one or morecoats of enamel prior to application of the textured finish coat.

left in place during the firing. During the firing operation,

the glass fiber cloth disintegrates. It apparently remains intact longenough, however, so that its texture is permanently imprinted into thesurface of the finish coat. On completion of the final firing, andcooling, the disinte grated remains of the glass fiber cloth are removedby brushing or other means to prevent injury to persons using theproduct.

The particular composition of the enamel used is not critical to thesuccess of the invention, and any of the conventional enamelformulations may be used successfully.

By the same token, the particular glass fiber cloth is not a criticalmatter. Good results have been achieved using relatively coarse gradesof cloth designed for industrial filtration or construction offiberglass-reinforced plastic structures such as boat hulls and thelike. Examples of such materials include Johns-Manville .032 cloth andJohns-Manville 0.16 cloth. Equally good results have been obtained usingfibrous glass drapery materials such as are used for interiordecorating, these giving, as might be expected, a much finer texturedsurface. The glass fiber cloth may be either woven or knitted, althougha majority of commercially available glass fiber cloths are of the wovenvariety.

When the method of this invention is used to produce colored designs onthe textured surface, any of the conventional materials commonly usedfor coloring ceramic objects may be used. In many cases, these arematerials which are also used for dying glass fiber cloth, such as ironoxides, cadmium salts, and various other inorganic pigments well knownto the art. When applied to glass fiber cloth, such oxides arecustomarily bonded to the glass fibers by the use of a suitable resin orother appropriate adhesive. This invention may be practiced by usingappropriate commercial glass fiber materials already bearing the desiredcolors or designs, provided the materials used to color the materialsare stable at the temperatures used for firing the enamelware. In thecourse of the firing, the binder is burned off, and the pigment istransferred from the glass fiber cloth to the surface of the enamel. Ifdesired, the invention may also be practiced by starting with plainglass cloth and applying the coloring oxides thereto in any convenientmanner such as the conventional methods for applying colorants to glasscloth materials, and the resulting colorant-bearing glass cloth used inthe same way as above described.

The glass fiber cloth may be simply laid on the unfired enamel surface,or it may be pressed down lightly to fix it in place and help assurefaithful reproduction of the cloth texture in the enamel.

After the glass fiber cloth is in place, the article is tired in aconventional firing cycle depending on the com- 7 position of theenamel. No change in firing conditions is necessitated by the presenceof the glass cloth, although when the glass cloth is used to applycolors to the article, the nature of the particular colorant selectedmay require some. adjustment in firing conditions, .aswill, be obviousto those familiar 'with such colorants and their application toenamelware articles.

Although'the particular type of glass fiber cloth is subject to wid'elatitude depending on the effects desired, it is apparently necessary toemploy a glass cloth. Similar materials such as asbestos cloth, whichmight be expected to show similar results, fail to produce a non-skidtextured surface. v v e e In order to illustrate morefully the nature ofthis invention and the manner of practicing the same, the followingexamples are presented.

EXAMPLE 1 Cover coat enamel formula I Parts by weight Borax, anhydrous-44 Whiting 84 Antimony oxide 74 Nitrate of soda 75 Sodium silicofiuoride20 Titanium dioxide 60 Lead silicate 133 Soda ash A cast iron workpiece,for example a lavatory basin, is provided with a conventional base coatand the base coat is fired in a furnace for an appropriate time at anappropriate temperature to properly mature the base coat, for example,for 10 minutes at 1725 F.

The workpiece is then removed from the furnace and (while still hot) iscovered with a cover coat of dry, powdered cover enamel of the abovecomposition, applied by dusting from a sieve. The workpiece is thenreturned to the furnace and heated sufficiently to melt the enamel coatto a smooth, glossy surface.

The workpiece is again removed from the furnace and a second cover coatof dry, powdered cover enamel is applied in substantially the samemanner as the first cover coat, after which a glass fiber cloth isplaced in contact with the portion of the workpiece to be textured, andthe workpiece with the glass fiber cloth is returned to the furnace andfired in the same manner as for the first cover coat.

After the firing of the second cover coat, the workpiece is removed fromthe furnace and allowed to cool. The texture portion of the workpiece isbrushed lightly to remove the loose flakes of material remaining fromthe disintegration of the glass fiber cloth. The portion of theworkpiece which has been fired in contact with the glass fiber cloth hasa textured, non-skid, easily cleanable surface of pleasing appearancecorresponding to the texture of the glass fiber cloth.

, EXAMPLE 2 The procedure of Example 1 is repeated, except that theglass fiber cloth is not applied to the second cover coat prior tofiring thereof. Instead, the second cover coat is fired in the samemanner as the first cover coat. The workpiece is then removed from thefurnace, the fiberglass is applied to the desired portion of theworkpiece, and the workpiece is returned to'the furnace and lightlyfired, sufiiciently 'to permit the texture of the glass fiber cloth tobe impressed into the surface of the second cover coat. The workpiece isthen removed from the furnace, cooled and brushed as described inExample 1. The resulting product is similar to that produced accordingto Example 1.

5 EXAMPLE 3 The procedure of Example 1 is repeated, except that theglass fiber cloth employed is a tinted cloth, colored blue by the use ofa cobalt-chromium composition. The resulting textured workpiece issimilar to that produced according to Example 1, except that thecobalt-chromium is transferred to the enamel during the firing of thesecond cover coat, and the finished workpiece is colored blue in thetextured area.

While this invention has been described with reference to certainpreferred embodiments of the invention, these are illustrative only, asmany alternatives and equivalents will readily occur to those skilled inthe art, without departing from the spirit or proper scope of theinvention. The inventon is therefore not to be construed as limited,except as set forth in the appended claims.

What is claimed is:

1. A method for producing an enamelware article having a patternedsurface, said method comprising in combination the steps of applying toan object to be enameled a coating of dry enamel powder, placing incontact with said coating 2. glass fiber cloth, firing said dry enamelpowder and said glass fiber cloth in contact therewith, and removingresidual particles of said glass fiber cloth from said article afterfiring and cooling thereof.

2. A method according to claim 1, wherein said glass fiber cloth isplaced in contact with said coating while said object is at elevatedtemperature.

3. A method for producing an enameled article having thereon a design ofa color different from, the color of said enamel, said method comprisingin combination the steps of applying to an object to be enameled acoating of dry enamel powcler, placing in contact with said coating aglass fiber cloth having a ceramic colorant thereon, firing said enamelcoating and said glass fiber cloth and colorant in contact therewith,and removing residual particles of said glass fiber cloth from saidarticle after firing and cooling thereof.

4. A method according to claim 3, wherein said glass fiber cloth isplaced in contact with said coating while said object is at elevatedtemperature.

5. A method according to claim 3, wherein said ceramic colorant isinitially present on said glass fiber cloth as a dispersion of inorganicpigment particles.

6. A method according to claim 3, wherein a multicolored design isapplied to said glass fiber cloth, and said design is transferred tosaid enamelware article by firing said enamelware article and said glassfiber cloth in contact therewith.

References Cited UNITED STATES PATENTS 1,503,695 8/1924 McPherson 117-102,292,369 8/ 1942 Gordon. 2,728,698 12/1955 Rudner 2646O FOREIGN PATENTS94,933 2/1963 Denmark.

DAVID KHFIIN', Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,453,133 July 1, 1969 William C. Cawthon et a1.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 3, line 41, "Johns-Manville 0.16" should read Johr Manville .016

Signed and sealed this 22nd day of December 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, 11'.

Attesting Officer

